I used brake cleaner for a while, then switched to mureatic acid. Let the plate and intake soak for about an hour each, then scrubbed away what was left. As a word of caution, you will want to use gloves and goggles to protect yourself a little bit.

Is there anything I can get easily that I can soak it in? I have super clean degreaser (spray) which takes off the oil very easy just wipe and it comes off but it says prolonged use on aluminum isn't good so I don't want to soak it .

Do I have to soak it? I have the inside of the intake very clean. Just the chambers (all) have oily throughout them I think